The chapel in the US military's Camp Leatherneck, Helmand Province, Afghanistan. Along with religious ceremonies the chapel is used as a meeting place for soldiers to relax, drink coffee and attend classes dealing with anything from marriage counselling to bible studies. Photograph: Sergeant Alison Baskerville RLC

It is often said America and England are two nations separated by a common language. The same could be said about their religious practices.

On the corner of Echo and 5th Street in Camp Leatherneck - the US equivalent of Camp Bastion in Helmand - is a building identical to the others surrounding it - mass-produced and military. Its interior, however, is nothing short of a revelation. It houses the chapel for US Christians in the armed forces, laying on standing room only services on a Sunday morning, prayer squares, guitar solos from its resident praise team and a lavish beverage station featuring two types of cookie and flavoured syrups for your freshly brewed coffee. Satin, fringed banners hang from the walls bearing phrases such as "Lamb of God" and "Lion of Judah".

"We named the chapel the oasis, we are in the middle of a desert and it is a physical and spiritual wilderness," says Padre Mucha ("like run amok"), chaplain to the US Navy and US Marine Corps. "There is a perception that we are a Christian country because of the Founding Fathers. But it is a great challenge to stay focused on the Lord in this day and age when you are around so many people who aren't."

Four servicemen - three US and one Briton - are being baptised in the chapel's custom built tank. Before this occasion, there is the not so small matter of evening worship. Padre Mucha is on stage, while before him a congregation that is multi-racial, young and mostly but not exclusively male rocks out to songs such as All Those Who Are Thirsty and We Want to See Jesus Lifted High. Hands lift, eyes close and feet tap.

The US members of the congregation are either carrying their weapons or have propped them up against the wall. It is a standing order for all US military to carry their weapons in theatre at all times - even in church.

Padre Cole, a British chaplain from Camp Bastion, is giving the sermon and dons a headset, telling the congregation: "I feel like Kylie Minogue wearing this. You should be so lucky. Lucky, lucky, lucky." His patter is part stand-up, part clergyman and he walks around the lectern, referencing Wesley Snipes, the sitcom Friends and the seven names of God in Hebrew.

One of the baptism services at Camp Leatherneck. Photograph: Sergeant Alison Baskerville RLC

He later dispenses with his military uniform, as do the baptismal candidates, appearing from the side of the chapel in T-shirt, flip-flops and shorts. One by one the young servicemen enter the tank. Some hold their noses, others don't, before they are immersed into the water. One candidate loses his shoes. They emerge to applause, murmurs of "Praise Jesus" and smartphone photography. The ceremony ends with 60 people singing Amazing Grace while the sun sets over the barren landscape.

Major Harbour of 1st Battallion 23rd Marines is on his fourth tour. Three of them have been in Iraq. This is his first in Afghanistan. He says: "This deployment has solidified my faith. Our faith helps us get through the tougher times. We have a solid foundation to bring the US military. Atheists can bring a contribution to the military. All walks of faith and religion can bring something to the US military, not just Christians. However the Bible is very specific about what God says about other religions."

Religious affairs correspondent Riazat Butt is travelling through Afghanistan with army chaplains. She starts her blog looking at vigils for dead soldiers, and will send shorter posts throughout the next two weeks